High pressure steam plant with multistage power engine



1932- w. ABENDROTH 1,869,361

HIGH PRESSURE STEAM PLANT WITH MULTISTAGE POWER ENGINE Filed July 8, 1926 40 mossy/1r FALLl/V TEMP- FR)? uKE Patented Aug. 2, 1932 UNITED STATES WILHELM ABENDROTH, OF BERLIN-CHARLOTTENBU RG, GERMANY, .ASSIGNOR TO SIB- MENS-SCHUCKEBTWEBKE GESELLSGHAFT MIT BESCHRANKTER HAFT'U'NG, 0F SIE- MENSSTADT, GERMANY, A GERMAN CORPORATION HIGH PRESSURE STEAM PLANT WITH MULTISTAGE POWER ENGINE Application filed July 8, 1926,. Serial No My invention relates to a high pressure steam plant with multistage power engine.

According to my invention the steam supply to the high pressure part of the steam power engine is regulated in dependence from admission temperature of the superheated high pressure steam while the low pressure part is regulated in the customary manner in response to the load. Between the high and low pressure part of the power engine is provided a heat accumulator which stores the steam given ofi' in excess by the high pressure engine when carrying a low load in order to feed it to the low pressure part when the load rises. When in case of reduced steam requirement the accumulator is nearly fully loaded up, the supply of heat to the steam generator is reduced in known manner in dependence from the state of charge of the accumulator. Conversely the supply of heat to the steam generator is increased when the load increases and the accumulator contents consequently decreases. This is accomplished by a device which responds to the state of charge of the accumulator, and which automatically controls the heap supply to the steam generator accord- 111 3Z1 embodiment of my invention is illustrated diagrammatically in the drawing aifixed hereto.

Referring to this drawing, 1 is the high pressure steam boiler from which the steam of a superheating temperature of approximately 400 C. flows through the pipe 2 to the high pressure turbine 3. After the steam has performed its work therein, it flows through the intermediate superheater 4 by way of conduit 14 to the low pressure part of the prime mover. The two prime movers 3 and 5 should preferably remain in synchronous speed relation to each other, which may be brought about for instance by coupling the shafts of both prime movers together as shown. The exhaust from this part 5 is condensed in the condenser 6 and conveyed into the feed-water tank 8 by the pump 7 whence the water of condensation is returned into the steam generator 1 by the centrifugal feed pump 9 in known manner.

. 121,179, and in Germany July 14, 1925.

' Feed pump 9, as shown, is of the centrifugal type which, as is well known,'has the peculiar characteristic that, with the assumption of for instance radial blades, the head remains constant with increase in quantity delivered by the pump. Therefore, for a given pump speed the pressure in the delivery conduit of the pump remains automatically substantially constant for varying quantities of water discharged into the boiler, (of course, within the proper operating capacity range of the pump). The use of such centrifugal pumps for feeding varying quantities of liquid at constant pressure has been known in the art and has been general engineering practice for a long time, and is favored on account of these characteristics.

According to my inventiona thermostat 10 is placed into' the service pipe 2 which actuates a control valve 12 which in turn thus controls the steam supply to the high pressure engine 3. Thermostats and valves controlled thereby being well known in the art, these elements are illustrated only diagrammatically, merely to indicate their location in the system. If the temperature of the steam risesv be yond a permissible measure care must be taken to bring about a reduction of the temperature by an increased circulation of the working medium. Thermostat 1'0 accomplishes this by opening admission valve 12 further on rising temperature, so that more vsteam flows into the high pressure stage 3. The low pressure steam admission to low pressure prime mover 5 is controlled by a governor 19, acting on admission valve 20 interposed between conduit 14 and engine 5. This governor acts in the usual manner, throttling the steam supply whenthe speed of the engine increases. If now, with the aforementioned assumption of increased steam supply to the high pressure engine 3 owing to increased steam temperature, the load on the prime mover system (for instance by smaller current demand on electric generator 18) i should decrease, the prime mover set receiving more high pressure steam, would tend to run faster, which is counteracted by governor 19 which then throttles the low pressure steam .creased amount of steam discharged' from supply to engine 5. Consequently, the inhigh pressure engine 3 cannot'be consumed by engine 5 and is now absorbed by the heat accumulator 13. The admission into the acdetails are omitted in the present arrangevalve 20 further.

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As excess steamis thus stored in accumulator 13 its water level rises. With the accumulator is connected a device, of any well known construction responsive to varying water levels therein. It is illustrated in the drawing diagrammatically by a float 22. This device controls the heat supply to the generator 1, which is indicated also diagrammatically by a valve 16 controlling fuel nozzle 15 of the generator and actuated itself by level responsive device 22. Thus with the foregoing assumption of excess steam supply to the accumulator, its water level will gradually rise and the heat supply to the generator be correspondingly decreased. In the case of an oil furnace, for instance, as indicated in the drawing by the reference numeral 15, the burner valve 16 is throttled. It will be understood that naturally the supply of combustion air must also be regulated accordingly. This feature is not illustrated as obvious to those skilled in the art. In this way the temperature of the high pressure steam delivered through service pipe 2 is lowered, which now causes thermostat 10 to correspondingly move valve 12 toward its closing position.

If during such a drop'in steam temperature, with valve 12 further closed, the load on the prime movers should suddenly increase, the governor 19 would first of all call for increased steam supply to engine 5 by opening Since, however, the exhaust steam supply from engine 3 throu h conduit 14 is not very large owing to t e throttled fresh steam supply, the accumulator 13 makes up this deficiency and thus releases the steam previously stored. Thereby the water level in the accumulator is lowered and now float device 22 again comes into action, this time increasing the heat supply to the generators. This in turn has the effect of increased high pressure steam temperature to which thermostat 1O responds by opening valve 12 so that in this manner the entire generating system 12 is balanced in accordance with the new load conditions.

By the thermostatic regulation of the steam admission control gear for the high pressure stage of the power engine accordin to my invention the result is obtained by simple and reliable means that, on one hand, the admission temperature of the steam cannot drop below a certain value, the maintenance of which is desirable in the interest of a temperature head as high as possible, and that,

steam cannot rise beyond the value permissible for the constituent parts of the power engine.

Various modifications and changes may be made without departing from the spirit and the scope of the invention, and I desire, therefore, that only such limitations shall be placed thereon as are imposed by the prior art.

I claim as my invention 1. A steam plant having a steam generator and heat supply means therefor, a high pressure steam consumer supplied directly from said steam generator, a low pressure steam consumer having variable load demands and being supplied with exhaust steam from the high pressure consumer, and means for controlling the steam supply to the low pressure consumer in accordance with its demands, a steam accumulator disposed to receive or release steam when the amount of steam discharged by the high pressure consumer is not in accordance with the steam demand of the low pressure consumer, and means responsive to the state of charge of said accumulator for controlling the heat supply means to the steam generator inversely to the charged condition of said accumulator.

2. In a steam power plant in combination a steam generator having a heat supply, a high and a low pressure prime mover, a steam conduit from the generator to said high pressure prime mover and a conduit for supplying exhaust steam from the high pressure to the low pressure prime mover, means responsive to the low pressure prime mover speed variations for controlling its steam supply inversely with its speed variations, a steam accumulator connected to said exhaust-conduit and adapted to store or release steam whe'n'the amount of steam discharged from the high pressure prime mover is not in accordance with the. demand of the low pressure prime mover, and means responsive to the varying state of accumulator charge for controlling the generator heat supply inversely to the accumulator charge.

3. In a steam power plant in combination a steam generator having a heat supply, a high and a low pressure prime mover coupled to operate at synchronous speeds, a steam supply connection between said generator and said high pressure prime mover and a conduit for supplying the exhaust steam from the high pressure to the low pressure prime mover, a steam accumulator connected to said exhaust conduit, means responsive to the prime mover speed for varying the exhaust steam supply to the low pressure prime mover inversely with the prime mover speed, and means responsive to the varying state of the accumulator charge for controlling the heat supply to said generator inversely to the accumulator charge, whereby the surplus steam available from the high pressure on the other hand, the temperature of the prime mover at the speed increase of the prime movers is stored in the accumulator and the heat supply to the generator is reduced with the increase of steam storage in the accumulator.

4. In a steam power plant in combination a steam generator having a heat supply, a high and a low pressure prime mover coupled to operate atsynchronous speeds, a steam supply connection between said generator and said high pressure prime mover and a conduit for supplying the exhaust steam from the high pressure to the low pressure prime mover, a steam accumulator connected to said exhaust conduit, means responsive to the prime mover speed for varying the exhaust steam supply to the low pressure prime mover inversely with the prime mover speed, and means responsive to the varying state of the accumulator charge for controlling the heat supply to said generator inversely to the accumulator charge, and temperature responsive means in the generator steam supply for controlling the steam supply to the high pressure prime mover in accordance with the generator steam temperature variations, whereby any surplus steam available from the high pressure prime mover is stored in the accumulator, and the steam supply to the high pressure prime mover is increased with the temperature of the steam supplied from the generator, and whereby the heat supply to the generator is reduced with the increase of steam storage in the accumulator.

In testimony whereof I aifix my signature.

WILHELM ABENDROTH. 

